Topic: Regulator adjustment

[Evel E.]

Hello,

I'm trying to follow the steps at:

http://sohc4.us/?q=node/47

for adjusting the voltage regulator.  It would seem that at step four, if I disconnect the battery while the bike is running, the engine will die.  Is this not correct?  Can you run an sohc four batteryless?

-Eric

[TwoTired]

My opinion is that that part of the FAQ incorrect and written by someone who just doesn't quite understand how the circuit actually works.

But, to answer your questions...
Yes, you can keep the bike running after disconnecting the battery by keeping the alternator spinning fast enough to overcome the system loads and keep the alternator self excited. When there is not enough power to self excite the alternator output drops off, eventually to zero.

But, since I can't leave it alone... 
I believe there is risk of blowing some, or all, of the diodes in the rectifier while doing this though.  The battery dampens the voltage peaks and spikes that can stress those diodes.

The regulator's primary purpose it to keep the battery at full charge when the alternator is spinning fast enough to do so.  It is not there to maintain the bike's sytem voltage directly.  The battery actually does that as it's power contribution is many times what the alternator can provide.

Think of it like this.  The bike is the dam, the battery is the reservoir behind the dam, the voltage regulator is the gate that controls the reservoir capacity; trying to keep it full but never overflowing.

The process in that FAQ essentially makes the vreg believe the battery is not as full as it really is.  The risk is over filling and destroying the battery, albeit slowly.

Also, with the battery removed, it's damping effect on charging system output is eliminated.  This allows an AC component originated in the alternator to interfere with some meter's sensing and measurement ability.  You could get false readings.
Further, the bike's many interconnections can corrode over time, lowering the voltages throughout the bike.  The connectors between alternator and battery may have these added resistances.  If you adjust the regulator to compensate for these losses, and then later improve the inline connections in the future, the regulator must be readjusted to compensate, or risk damaging the battery.

The voltage regulator is best adjusted by the procedures laid out in the Honda Shop Manual.
I do not recommend using it to circumvent fixing problems elsewhere on the bike.

Cheers,

[dusterdude]

lloyd,perhaps someone(you maybe) should rewrite that faq and lets get it fixed.

[Evel E.]

Hello,

I thought that I posted a reply to this last night, but apparently not.  My charging system appears to be fine.  If anything the regulator is set too high.  My battery voltage gets around 15 V before the regulator appears to kick in. 

I had tested it earlier shortly after replacing my original blown (both elements!) sealed beam with a halogen.  At that time the engine had sat for a couple weeks and I had to crank and crank to get the engine to start.  Maybe the excited field alternator takes a while to start charging good with a weak battery, the battery voltage was like 12.5 to 13 Volts at 4000ish rpm.  I tested it last night and it's was 14 Volts or more at 4000 rpm.  One thing that I did notice was that the battery voltage takes a while to raise up after the engine is started.  After running a minute or two it had noticably more volts at idle than it did when it first started.  I guess this is a characteristic of excited field alternators.

I've cleaned out my carburetors and my bike's running and starting quite well now.  I also fixed a sticking float issue.  If I could just get to the bottom of my CB350 camchain adjuster mystery...

-Eric

lloyd,perhaps someone(you maybe) should rewrite that faq and lets get it fixed.

[bryanj]

Having used the electric start you have used a fair chunk of the batteries available power so it takes a while for the generator to recharge it to the maximum, this is nothing to do with the type of generator! Honda spec is a max 14.5 V before the regulator kicks in and that can easily be 15V on a cheaper meter